MEMS-based Reconfigurable Manifold Update Presentation at MAPLD 2005

1. MEMS-based Reconfigurable Manifold Update Presentation at MAPLD 2005 Warren Wilson‡, James Lyke‡ Joseph Iannotti* and Glenn Forman* ‡Space Vehicle Directorate/Air Force Research Laboratory *General Electric Global Research

2. Motivation for Reconfigurable Systems • Maximizes utilization of space assets to allow: • Recovering from faults (fault-tolerance) • Reconfiguration after deployment • Reconstituting / “refocusing” assets for current mission • Reconfiguring / “refocusing” assets for new missions • Single platform and distributed functionality • Accelerates the possibility of “space-on-demand” by enabling plug-and-play spacecraft • Adaptive interfaces to dramatically reduce the time for development, integration • Space logistics / remote servicing Wilson

3. Role of Adaptive Wiring in Reconfigurable Systems Reconfigurable digital Reconfigurable analog Reconfigurable microwave Reconfigurable power A/D D/A Adaptive Manifold of Reconfigurable Interconnections component sockets connectors A/D D/A discrete component patchboard Wilson

4. Reconfigurable analog • Programmable analog architectures • Configurable process chains • Alter gain, offset, filtration characteristics • Configurable analog blocks • Permits flexible arrangement of some analog building blocks • Limitations • Frequency of operation • Ranges of resistances, capacitances require supplemental, external, non-programmable discrete components Wilson

5. Reconfigurable Power • Permit alteration of input voltage, output voltage, and load conditions under software control • maintain optimal electrical efficiency under variations • Industry practice • Some configurable power technologies permit modular power supplies by manual arrangement of discrete building blocks (e.g., Lambda) • Smart-power approaches in microprocessors and FPGAs to permit different supply and I/O voltage levels Wilson

6. Reconfigurable Microwave • Emergent techniques • Direct digital synthesis (generated modulated carrier directly in real-time) • Reconfigurable antenna • Electronically steerable antenna • MEMS-based antenna reshaping • Other techniques to modify dielectric / conductor configurations of antenna under software control • Software radio • Minimize non-digital content of RF systems, permit agile manipulation of radio protocols for transceivers Wilson

7. Conventional Spacecraft Avionics Payload (s) C & DH Processor Interface Card COMM GNC Bus GNC Interface Card GNC Interface Card PMAD Interface Card telemetry Wilson

8. Reconfigurable Spacecraft Avionics FP FP FP FP FP FP Optical Sensor Adaptive Wiring Manifold MSP FP FP SpaceWire FP FP FP FP Legacy components MSP Software Radio SpaceWire comp. comp. Space -wire Plug-and-play network MSP SpaceWire MSP SpaceWire C&DH Interface Interface COMM MSP SpaceWire MSP = Malleable Signal Processor FP = Fusion Processor Compact PCI bus Command & Data Handling Wilson

9. Adaptive Manifold • Reconfigurable switch manifold used to program front end electronics and signal/processing paths of a satellite • Enabling the ability to break or make conductive pathways at will • Permit maximal use of a scarce satellite resource • Effectively re-route the signal paths to optimize the extractable data • Correct defects found during construction/integration/mission • Applied as the interface of self-configuring systems, the idea would be equivalent to an advanced plug-and-play • where choice of each pin location and its impedance characteristics could be re-definable at will Wilson

10. Adaptive Manifold II • Such a manifold would required • Locally embedded relays: hundreds or thousands of switches distributed among a circuit's interconnections • A configuration control system: which would set the “0s” and “1s” of each particular relay • E.g., programmed by a bitstream generation process • Currently used in certain digital field programmable gate array (FPGA) system • A MEMS-based “smart substrate” can handle signals with extreme excursions in amplitude and frequency • The complete separation of the switched circuit from the switching circuit is an advantage when cascading switches within the manifold • The MEMS switches can operate under voltage constrains that would take a transistor switch out of saturation, or worse, cause device breakdown Wilson

11. Conventional vs. Adaptive Wiring Manifold Box Box Box Box Box Box Box Box Box Box open closed Wilson

12. Programmable Connections AWM combines wiring, switches, and control to make arbitrary terminal-to-terminal connectivity possible in a wiring system Program switches using routing heuristics Program A-P connection Program A-P,C-K, F-Q-S connections Wilson

13. Adaptive Manifolds • Approaches to embed large numbers of micro-relays into packages, boards, and wiring harness • Strategies for reconfiguration • Algorithms for altering system configurations • Satellite itself becomes a large “field programmable device” • Concepts for repair-ability and extensibility • Disciplines for design and application of reconfigurable systems Smart-wiring based avionics system Dockable-assemblies Satellite-as-a-device Wilson

14. Payload Attachment Pointsand Switch Resource Distribution Example population strategy Latching Digital (FPID) – 75% switchbox MEMS – 10% switchbox Mounting site Solid state power – 10% switchbox switchbox Macro EM – 5% fixed switchbox switchbox switchbox switchbox Mounting site switchbox switchbox fixed • Mounting sites contain terminals connected to one of six types of wiring resources • Four wiring types (volatile and non-volatile, MEMS, non-MEMS) • Fixed (common connections) • Configuration (future) • Wiring resources contained in switchboxes Wilson

15. Summary of switch requirements for an adaptive manifold • Bistable / multistable • Electrical performance • Low resistance • High bandwidth • High-isolation (low crosstalk) • Hot-switching • High melting contacts • Mechanical performance • 50 micron gap • Sets maximum switching voltage • 2 micron thick gold alloy contracts • Sets lifetime under hot switching • 0.2 m/s contact velocity • Related to hot switching lifetime • 70 mΩ constriction resistance • Sets maximum cold current • 50/200 μs lag open/close time • Sets maximum relay duty cycle Wilson

16. Latching Relay Requirements Wilson

17. Magfusion’s RF Latching Relay Moving contact pad Fixed contact pad Coil contracts Moving contact (teeter-totter) Torsion suspensions Wilson

18. Design of Avionics Manifold • Design is to arbitrarily connect among 3 payloads and 4 ports • The ports connect to additional panels • Each payload allows 12 connections: 10 RF, 2 power • Construct a macro-relay version of a simple manifold • 260 latching MEMS RF metal-to-metal relays in a “mesh” configuration • 10 latching macro DC metal-to-metal relays to supply high current power • Circuit board on printed wiring board (10 layers) • Expected benefits • Development of control circuitry • Establish software algorithms and user-interface • Examine scaling issues Wilson

19. Circuit design for demo AWM North Payload 1 East Payload 2 South Payload 3 West • Circles represent connections • Open: selectable connections • Filled: fixed connections • Each line represents a set of individually switched circuits elements • 2 power, 10 RF, and logic • Compromise configuration • Limitation on number of MEMS RF switches available • N(N-1)/2 = >2,000 switches • N = (3+4)*10 • Demo configuration used only 260 MEMS RF latching switches Wilson

20. Implementation of AWM demo Magfusion Switch • Manifold is a panel based on flexible circuitry • “Payload sites” serve as points to mount subsystems or complex components • Switchboxes are small circuit boards containing • MEMS switches • Control ASIC • Microcontroller (CPU) used to manage switchbox configurations (e.g. JTAG interface or Robust USB) • Multiple panels can communicate partial configurations to form composite adaptive wiring assemblies Switchbox ASIC (ATK/MRC under AFRL Support) Other MEMS Switches Switchbox PAYLOAD SITE PAYLOAD SITE PAYLOAD SITE CPU Panel Wilson

21. AWM Components ASIM (Appliqué Sensor Interface Module) Payload Interface (USB, xTEDS) Front/back sides of Switchcard Video Capture over SPA-S, Video-PC_TV over SPA-U, Space-Cube and GPS Demonstration on One Panel: Meets Transfer Rates! R-USB configuration network Wilson

22. AWM Panel Configuration with Payload Cards AWM USB Configuration Interface (bottom side) Input for configuration and spacecraft power Payload Interface Card Panel to panel Connector USB Port One of 13 Switch Module Cards (using 10 latching Magfusion relays, 2 latching macro power switches relays mounted on underside of card) SpaceWire Port Wilson

23. Back View AWM Panel Configuration USB1.1 Hub card for on and off panel enumeration/control Switch Module Card (10 Magfusion Switches) (Total of 4 installed on bottom) AWM USB1.1 Configuration Interface Wilson

24. AWM Demo 2nd PC running Display2 Display: DVD movie 2nd Space Wire Board 1 Distinct SpaceWire interconnect routed via AWM for payload to payload interconnect 2 Distinct USB routes: TEDS – USB 1.1 TEDS interface used for enumeration and control USB – USB 1.1 (2.0 capable) interface routed via AWM for payload to payload interconnect Display: SPACEBALL rotating cube DVD player NI Frame Grabber 1st Space Wire Board SPACEBALL 3DM-GX1 OPC NORTH PAY 1 OPC WEST OPC EAST Panel 1 PAY 2 Display: AWM CONFIGURATION GUI PAY 3 TEDS (host) OPC SOUTH OPC NORTH PC running AWM CONFIG. SW (not needed once system configured) All panels, switch cards and hub cards are identical Payload cards are similar but have unique ID for function identification PAY 1 3DM-GX1 Inclinometer & Orientation Sensor OPC WEST OPC EAST Panel 2 PAY 2 PAY 3 Optional TEDS Port TEDS (slave) OPC SOUTH Wilson

25. RF Characteristics of AWM 2.7 GHz Diff Eye thru Switchcard and 15 inch of PCB Wilson

26. RF Characteristics of AWM 2.7 GHz Diff Eye Cables Alone Wilson

27. Take Away Items from AWM Demo • All passive (Relay) AWM will have length limitations that impact desired high speed SpaceWire performance • Latching switches are desirable but have seen issues with available array density • “Electronic” (FPIDS, FPGA’s, etc...) can provide configurable I/O’s and signal regeneration while providing adaptive routing features • System architecture may include optical interconnect for “Long Hauls”; thru an entire panel, acts as repeater as well • All passive backplane gives flexibility and producibility Wilson

28. Take Away Items from AWM Demo • Physical location/orientation of panels provide challenge in AWM routing • USB1.1 is convenient but has issues in this application with respect to upstream-downstream • At high speeds, un-terminated stubs due to unused routes are not tolerated • Higher density switching hardware minimizes stub length and as such minimizes number of switches needed • SpaceWire standard needs more work in the area of: • Tx and Rx mask spec • Acceptable Interconnect Degradation spec • Interoperability spec Wilson

29. Summary • Hopefully, AWM may do for spacecraft what FPGAs do for digital microelectronics • AWM is a ready consumer of MEMS relays • Excellent vehicle to study large-scale reliability • AWM will provide a meaningful set of ground and space experiments • Not limited to RF • Expected to have many non-space applications • The AWM concept is to be included and further developed in the responsive technology test cell located in the Responsive Space Testbed at the AFRL Space Vehicle Directorate, Kirtland AFB, NM Wilson

30. RE-CONFIGURABLE/ADAPTIVE MANIFOLD 28VDC payload attachment point 5VDC +15VDC Switch boxes -15VDC Spacecraft bus Subsystems Program high density interconnect between switchboxes VDC COMM_1 COMM_2 configuration management processor Analog_1 Analog_2 CMP Diagnostic Generic Adaptive Wiring Manifold Architecture • Concept: A software-definable wiring system • Pre-built (into structures), rapidly-programmable • Can be modified in orbit • Benefits: • Rapid integration on ground • Debug support (temporary probe wires) • On-orbit rewiring (fault, defect rectification) • Reliability and utility of MEMS switches Phase 1 – Construct exerciser panel; establish specs for switchboxes compatible with testable switches Phase 2 – Create space MEMS switch reliability experiment with diagnostics; require several hundred switches; 12-month spaceflight / Tacsat 4 (2007 launch) Phase 3 – Create non-toy space experiment based on adaptive wiring manifold; include at least four payload attachment sites; 12-month spaceflight / Tacsat 5 (2008 launch) • Objective is to Demonstrate: • Rapid payload integration • Space system reconfiguration • Systems on-orbit protection • Self-organizing sensor network • Adaptive MEMS-based wiring manifold • Reconfigurable RF system • Self-aware cognitive software Wilson